Evaluation of the Methodology for External Root Resorption Diagnosis Reproducibility

Objective: To evaluate the reproducibility of radiographs obtained with an individual positioning device when simulating orthodontic movement, by measurement of the dental length, visual comparison of radiographs pairs in monitor and qualitative digital subtraction radiography (DSR). Methods: 29 human extracted upper central incisors were radiographed at different inclinations in the bucco-palatal (BP) orientation: 0º baseline, 0º control, -10º, -5º, +5º e +10º. Radiographs were digitized and the teeth length were measured electronically through an image-analyser software. Pairs of images from the same tooth at different inclinations were showed on a screen to a blind observer for evaluation of the presence or absence (scores 1 to 5) of root length alteration. The same criteria were used to evaluate the DSR images from these pairs. Results: The linear measures of the roots’ length were reproducible (r=0.99) and there were no difference between groups with different inclinations (ANOVA, p=0.827). The evaluation through the pairs of images presented a lower correlation (r=0.413) but without statistical differences betwen groups with different inclinations (Friedman’s test, p=0.700). The evaluation through the DSR showed a good correlation (r=0.798) and there were no differences between the groups with different inclinations (Friedman’s test, p=0.379). Conclusion: The methodology proposed was capable of reproducing the images’ length at inclinations up to 20 degrees in the BP orientation, simulating orthodontic movement, when evaluated by linear measure and DSR.